القاعدة ذات الصلة
Peru
Practice Relating to Rule 20. Advance Warning
Peru’s IHL Manual (2004) states:
When the tactical situation permits, effective advance warning must be given of attacks which may affect the civilian population (infantry fire to encourage civilians to take shelter, dropping leaflets from a plane, etc.).
The warning should be given in good time so that safety measures can be taken to significantly reduce the harmful effects of armed conflict. 
Peru, Manual de Derecho Internacional Humanitario para las Fuerzas Armadas, Resolución Ministerial Nº 1394-2004-DE/CCFFAA/CDIH-FFAA, Lima, 1 December 2004, § 29.s; see also §§ 29.b.(4) and 107.a.
The manual also states:
Only missions compatible with international humanitarian law can be planned.
Missions given to subordinates must include all the relevant details required to ensure respect for international humanitarian law (for example, appropriate preventive … warning measures). 
Peru, Manual de Derecho Internacional Humanitario para las Fuerzas Armadas, Resolución Ministerial Nº 1394-2004-DE/CCFFAA/CDIH-FFAA, Lima, 1 December 2004, § 24.a.(10).
Peru’s IHL and Human Rights Manual (2010) states:
When the tactical situation permits, effective advance warning must be given of attacks which may affect the civilian population (infantry fire to encourage civilians to take shelter, dropping leaflets from a plane, etc.).
The warning must be given sufficiently in advance so that safety measures can be taken to significantly reduce the harmful effects of the war. 
Peru, Manual de Derecho Internacional Humanitario y Derechos Humanos para las Fuerzas Armadas, Resolución Ministerial No. 049-2010/DE/VPD, Lima, 21 May 2010, § 30(s), p. 244; see also § 30(b)4, p. 242, and § 54, p. 424.
The manual also states:
Only missions compatible with international humanitarian law can be planned.
Missions given to subordinates must include all the relevant details to ensure respect for international humanitarian law (for example, appropriative preventive … warning measures). 
Peru, Manual de Derecho Internacional Humanitario y Derechos Humanos para las Fuerzas Armadas, Resolución Ministerial No. 049-2010/DE/VPD, Lima, 21 May 2010, § 25(a)(10), p. 227.